Persistent storage modules such as USB memory sticks and Secure Digital cards may be misplaced, lost or stolen. In such a circumstance, the lost storage modules may contain hundreds of megabytes of corporate, personal or otherwise proprietary data.
Persistent storage modules generally make no distinction between how secure data and non-secure data may be stored and accessed. Such modules often store data without regard to the proprietary nature of the data they are storing. Thus, applications often have to separately encrypt their proprietary data with an application-specific key when storing that data on a general-purpose, removable memory module. Further, some computer operating systems include the capability to encrypt, and decrypt, data written to, and read from, a memory module. However if the module is coupled to a device that does not support cryptographic operations, access to encrypted stored data is prevented.